Japanese Knotweed – How Do You Protect Yourself When Purchasing A Property?


Japanese Knotweed is classified by the World Conservation Union as one of the World’s 100 worst invasive species. In fact, it is so invasive that it can cause damage to the foundations of a building.

The potential damage to buildings can render properties subject to Japanese Knotweed uninsurable. Mortgage lenders are likely to refuse an application if Japanese Knotweed is found on a site.

Japanese Knotweed – Beware when purchasing a property

If you are purchasing a property, how can you make sure that it is free of Japanese Knotweed?

The seller of a property is not under a duty to disclose any information about its physical condition. This is known as caveat emptor (or 'buyer beware').

When your conveyancing solicitor raises enquiries, it is possible to ask a specific question about Japanese Knotweed. Also, if you are purchasing a commercial property, the Commercial Property Standard Enquiries ('CPSE') will generally be used. Enquiry 8.1(d) asks for details about 'rising damp, rot, any fungal or other infection or any infestation'. Enquiry 15.7 asks for details of any environmental problems relating to the property. Arguably, both of these enquiries would apply to Japanese Knotweed.

However, the seller is not obliged to answer any pre-contract enquiry and may reply "please rely on your own investigations". As a result, simply raising an enquiry is often not enough to eradicate the risk of Japanese Knotweed.

An "Environmental Desktop Search" might appear to be a solution. However, these reports rely on publically available information; they do not include a visit to the site. An Environmental Desktop Search cannot therefore reveal whether Japanese Knotweed is present on a site.

The only safe way to guard against Japanese Knotweed is to commission a survey on the issue from either a Surveyor or an Environmental Consultant.

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